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John R. Williams. Cook, Benjamin Koger, 1965- Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering. Massachusetts Institute of Technology. Department of Civil and Environmental Engineering 2005-08-23T18:29:10Z 2005-08-23T18:29:10Z 2001 2001 http://hdl.handle.net/1721.1/8231 50177817 Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001. Includes bibliographical references (p. 129-136). Our understanding of solid-fluid dynamics has been severely limited by the nonexistence of a high-fidelity modeling capability for these multiphase systems. Continuum modeling approaches overlook the microscale solid-fluid interactions from which macroscopic system properties emerge, while experimental inquiries have been plagued by high costs and limited resolution. One promising numerical alternative is to simulate solid-fluid systems at the grain-scale, fully resolving the interaction of individual solid particles with other solid particles and the surrounding fluid. Until recently, the direct simulation of these systems has proven computationally intractable. In this thesis an accurate, efficient, and robust modeling capability for the direct simulation of solid-fluid systems is formulated and implemented. The coupled equations of motion governing both the fluid phase and the individual particles comprising the solid phase are solved using a highly efficient numerical scheme based on the discrete-element (DEM) and the lattice-Boltzmann (LB) methods. Particle forcing mechanisms represented in the model to at least the first order include dynamic fluid-induced forces, buoyancy forces, and intergranular forces from particle collisions, static formation stresses, and intergranular bonding. Coupling is realized with an immersed moving boundary scheme that has been thoroughly validated. (cont.) For N solid bodies under simulation, the coupled DEM-LB numerical scheme scales roughly as O(N), and is highly parallelizable due to the local and explicit nature of the underlying algorithms. The coupled method has been implemented into a generalized modeling environment for the seamless definition, simulation, and analysis of two-dimensional solid-fluid physics. Extensive numerical testing of the model has demonstrated its accuracy and robustness over a wide range of dynamical regimes. Various fundamental phenomena have been reproduced in simulations, including drafting-kissing-tumbling interactions between settling particles, and the saltating transport regime of bed erosion. by Benjamin Koger Cook. Sc.D. 136 p. 18546802 bytes 18546555 bytes application/pdf application/pdf eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Civil and Environmental Engineering. A numerical framework for the direct simulation of solid-fluid systems Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="7d074ada-a452-475d-8973-271b8ce4d136"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>A numerical framework for the direct simulation of solid-fluid systems</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2001</PublicationDate> <Authors> <Author> <DisplayName>Cook, Benjamin Koger, 1965-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Civil and Environmental Engineering.</Keyword> <Abstract>Our understanding of solid-fluid dynamics has been severely limited by the nonexistence of a high-fidelity modeling capability for these multiphase systems. Continuum modeling approaches overlook the microscale solid-fluid interactions from which macroscopic system properties emerge, while experimental inquiries have been plagued by high costs and limited resolution. One promising numerical alternative is to simulate solid-fluid systems at the grain-scale, fully resolving the interaction of individual solid particles with other solid particles and the surrounding fluid. Until recently, the direct simulation of these systems has proven computationally intractable. In this thesis an accurate, efficient, and robust modeling capability for the direct simulation of solid-fluid systems is formulated and implemented. The coupled equations of motion governing both the fluid phase and the individual particles comprising the solid phase are solved using a highly efficient numerical scheme based on the discrete-element (DEM) and the lattice-Boltzmann (LB) methods. Particle forcing mechanisms represented in the model to at least the first order include dynamic fluid-induced forces, buoyancy forces, and intergranular forces from particle collisions, static formation stresses, and intergranular bonding. Coupling is realized with an immersed moving boundary scheme that has been thoroughly validated.</Abstract> <Abstract>(cont.) For N solid bodies under simulation, the coupled DEM-LB numerical scheme scales roughly as O(N), and is highly parallelizable due to the local and explicit nature of the underlying algorithms. The coupled method has been implemented into a generalized modeling environment for the seamless definition, simulation, and analysis of two-dimensional solid-fluid physics. Extensive numerical testing of the model has demonstrated its accuracy and robustness over a wide range of dynamical regimes. Various fundamental phenomena have been reproduced in simulations, including drafting-kissing-tumbling interactions between settling particles, and the saltating transport regime of bed erosion.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>